A Double-blind Study to Assess the Efficacy and Safety of Intranasal Esketamine for the Rapid Reduction of the Symptoms of Major Depressive Disorder, Including Suicidal Ideation, in Participants Who Are Assessed to be at Imminent Risk for Suicide

Percentage of Participants With Sustained Response Based on MADRS Total Score (Double-blind Phase)

Sustained response is defined as a reduction from baseline in MADRS total score of greater than or equal to 50 percent, with onset on Day 1 that is maintained through the end of the double-blind phase (Day 25). The MADRS consists of 10 items that cover all of the core depressive symptoms (apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts). Each item is scored from 0 (item is not present or is normal) to 6 (severe or continuous presence of the symptom). A total score (0 to 60) is calculated by adding the scores of all 10 items. For each item as well as the total score, a higher score represents a more severe condition. The LOCF approach was used for missing visit data in the ITT LOCF efficacy analyses.

Time frame: Day 1 to Day 25

Change From Baseline to Day 2 in MADRS Total Score (Double-blind Phase)

The MADRS consists of 10 items that cover all of the core depressive symptoms (apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts). Each item is scored from 0 (item is not present or is normal) to 6 (severe or continuous presence of the symptom). A total score (0 to 60) is calculated by adding the scores of all 10 items. For each item as well as the total score, a higher score represents a more severe condition. The LOCF approach was used for missing visit data in the ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 2

Change From Baseline to Double-blind Phase-End Point (Day 25) in MADRS Total Score (Double-blind Phase)

The MADRS consists of 10 items that cover all of the core depressive symptoms (apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts). Each item is scored from 0 (item is not present or is normal) to 6 (severe or continuous presence of the symptom). A total score (0 to 60) is calculated by adding the scores of all 10 items. For each item as well as the total score, a higher score represents a more severe condition. The LOCF approach was used for missing visit data in the ITT LOCF efficacy analyses. The last post baseline observation was carried forward as the "End Point" for the double-blind phase.

Time frame: Baseline (Day 1-predose) to Double-blind Phase-End Point (Day 25)

Percentage of Participants With Response Based on MADRS Total Score During the Double-Blind Phase

Percentage of participants with response (greater than or equal to (\>=) 50% improvement from baseline in MADRS total score) during the double- blind phase was assessed. The MADRS consists of 10 items that cover all of the core depressive symptoms (apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts). Each item is scored from 0 (item is not present or is normal) to 6 (severe or continuous presence of the symptom). A total score (0 to 60) is calculated by adding the scores of all 10 items. For each item as well as the total score, a higher score represents a more severe condition.

Time frame: Day 1 (4 hours postdose), Day 2 (double blind phase), Double blind phase -Endpoint (Day 25)

Percentage of Participants With Response Based on MADRS Total Score at Follow up Phase Endpoint

Percentage of participants with response (greater than or equal to (\>=) 50% improvement from baseline in MADRS total score) during the follow up was assessed. The MADRS consists of 10 items that cover all of the core depressive symptoms (apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts). Each item is scored from 0 (item is not present or is normal) to 6 (severe or continuous presence of the symptom). A total score (0 to 60) is calculated by adding the scores of all 10 items. For each item as well as the total score, a higher score represents a more severe condition.

Time frame: Follow up phase-endpoint (Day 81)

Change From Baseline to Day 1: 4-hours Post-dose in Suicide Ideation and Behavior Assessment Tool (SIBAT)-Clinical Global Judgment of Suicide Risk (CGJ-SR) Module 8 Score (Double-blind Phase)

SIBAT CGJ-SR: Module 8 operates numerous clinical global impression (CGI) severity scales used in other psychiatric studies. Changes in CGJ-SR designed to categorize clinically meaningful changes in clinician rated suicide risk from 'not at all suicidal' to 'participant is at imminent risk of suicide and immediate need for strong intervention (hospitalization with 24 hour 1:1 observation).' Patient scores for clinician-rated suicide risk: 0 (not suicidal); 1(occasional suicidal ideas, no intervention required);2(some clear suicidal ideas present),3(suicidal risk requires scheduled outpatient follow-up,no immediate intervention),4(suicidal risk requires immediate intervention, no hospitalization). 5( suicidal risk requires immediate hospitalization, no suicide precautions),6 (suicide risk requires hospitalization with suicide precautions). LOCF approach used for missing visit data in ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 1: 4-hours Postdose

Change From Baseline to Day 2 in Suicide Ideation and Behavior Assessment Tool (SIBAT)-Clinical Global Judgment of Suicide Risk (SIBAT CGJ-SR) Module 8 Score (Double-blind Phase)

SIBAT CGJ-SR: Module 8 operates like numerous other CGI severity scales used in other psychiatric studies. Changes in CGJ-SR designed to categorize clinically meaningful changes in clinician rated suicide risk from 'not at all suicidal' to 'participant is at imminent risk of suicide and immediate need for strong intervention (hospitalization with 24 hour 1:1 observation).' Patient scores for clinician-rated suicide risk: 0 (not suicidal); 1(occasional suicidal ideas, no intervention required);2(some clear suicidal ideas present),3(suicidal risk requires scheduled outpatient follow-up,no immediate intervention),4(suicidal risk requires immediate intervention, no hospitalization). 5( suicidal risk requires immediate hospitalization, no suicide precautions),6 (suicide risk requires hospitalization with suicide precautions). LOCF approach used for missing visit data in ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 2

Change From Baseline to Double-blind Phase-Endpoint (Day 25) Suicide Ideation and Behavior Assessment Tool (SIBAT)-Clinical Global Judgment of Suicide Risk (SIBAT CGJ-SR) Module 8 (Double-blind Phase)

SIBAT CGJ-SR: Module 8 operates like numerous other CGI severity scales used in other psychiatric studies. Changes in CGJ-SR designed to categorize clinically meaningful changes in clinician rated suicide risk from 'not at all suicidal' to 'participant is at imminent risk of suicide and immediate need for strong intervention (hospitalization with 24 hour 1:1 observation).' Patient scores for clinician-rated suicide risk: 0 (not suicidal); 1(occasional suicidal ideas, no intervention required);2(some clear suicidal ideas present),3(suicidal risk requires scheduled outpatient follow-up,no immediate intervention),4(suicidal risk requires immediate intervention, no hospitalization). 5( suicidal risk requires immediate hospitalization, no suicide precautions),6 (suicide risk requires hospitalization with suicide precautions). LOCF approach used for missing visit data in ITT LOCF efficacy analyses. Last post baseline observation was carried forward as "End Point" for the double-blind phase.

Time frame: Baseline (Day 1-predose) to Double-blind Phase-Endpoint (Day 25)

Change From Baseline to Follow-up Phase-Endpoint (Day 81) in Suicide Ideation and Behavior Assessment Tool (SIBAT)-Clinical Global Judgment of Suicide Risk Score (Follow-up Phase)

SIBAT CGJ-SR: Module 8 operates like numerous other CGI severity scales used in other psychiatric studies. Changes in CGJ-SR designed to categorize clinically meaningful changes in clinician rated suicide risk from 'not at all suicidal' to 'participant is at imminent risk of suicide and immediate need for strong intervention (hospitalization with 24 hour 1:1 observation).' Patient scores for clinician-rated suicide risk: 0 (not suicidal); 1(occasional suicidal ideas, no intervention required);2(some clear suicidal ideas present),3(suicidal risk requires scheduled outpatient follow-up,no immediate intervention),4(suicidal risk requires immediate intervention, no hospitalization). 5( suicidal risk requires immediate hospitalization, no suicide precautions),6 (suicide risk requires hospitalization with suicide precautions). LOCF approach used for missing visit data in ITT LOCF efficacy analyses. Last post baseline observation was carried forward as "End Point" for follow up phase.

Time frame: Baseline (Day 1-predose) to Follow-up Phase-Endpoint (Day 81)

Change From Baseline to Day 1: 4- Hours Postdose in SIBAT-Patient-Reported Global Assessment of Suicide Risk (Module 6) Score (Double-blind Phase)

SIBAT was specifically developed to measure rapid change in suicidality, based on concerns that existing scales such as Beck Scale for Suicidal Ideation (BSS) are not designed to discriminate differences associated with rapid change. Patient-rated section includes following modules: Module 1 (M-1)(demographic information,suicide history), M-2(current suicidal thinking),M-3 (protective factors), M-4 (suicide behavior),M-5(suicide risk),M-6(suicide-implicit association test).Patient-reported global assessment of suicide risk summarizes patient's judgment of suicide risk (Module 6). Scores: 0(None), 1(Very weak), 2(Weak), 3(Moderately weak), 4(Mild), 5(Moderate), 6 (Moderately strong), 7(Strong), 8(Extremely strong), 9(Extremely strong,constant). Negative change in score indicates improvement. LOCF approach used for missing visit data in the ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 1: 4-hours postdose

Change From Baseline to Day 2 in Suicide Ideation and Behavior Assessment Tool Patient-Reported Global Assessment of Suicide Risk (Module 6) Score (Double-blind Phase)

SIBAT was specifically developed to measure rapid change in suicidality, based on concerns that existing scales such as BSS are not designed to discriminate differences associated with rapid change. Patient-rated section includes following modules: Module 1 (M-1)(demographic information,suicide history), M-2(current suicidal thinking),M-3 (protective factors), M-4 (suicide behavior),M-5(suicide risk),M-6(suicide-implicit association test).Patient-reported global assessment of suicide risk summarizes patient's judgment of suicide risk (Module 6). Scores: 0(None), 1(Very weak), 2(Weak), 3(Moderately weak), 4(Mild), 5(Moderate), 6 (Moderately strong), 7(Strong), 8(Extremely strong), 9(Extremely strong,constant). Negative change in score indicates improvement. LOCF approach used for missing visit data in the ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 2

Change From Baseline to Double Blind Phase-Endpoint (Day 25) in Suicide Ideation and Behavior Assessment Tool Patient-Reported Global Assessment of Suicide Risk (Module 6) Score (Double-blind Phase)

SIBAT was specifically developed to measure rapid change in suicidality, based on concerns that existing scales such as BSS are not designed to discriminate differences associated with rapid change. Patient-rated section includes following modules: Module 1 (M-1)(demographic information,suicide history), M-2(current suicidal thinking),M-3 (protective factors), M-4 (suicide behavior),M-5(suicide risk),M-6(suicide-implicit association test).Patient-reported global assessment of suicide risk summarizes patient's judgment of suicide risk (Module 6). Scores: 0(None), 1(Very weak), 2(Weak), 3(Moderately weak), 4(Mild), 5(Moderate), 6 (Moderately strong), 7(Strong), 8(Extremely strong), 9(Extremely strong,constant). Negative change in score indicates improvement. LOCF approach used for missing visit data in the ITT LOCF efficacy analyses. Last post baseline observation was carried forward as "End Point" for double-blind phase.

Time frame: Baseline (Day 1-predose) to Double-blind Phase-Endpoint (Day 25)

Change From Baseline to Follow-up Phase-Endpoint (Day 81) in Suicide Ideation and Behavior Assessment Tool Patient-Reported Global Assessment of Suicide Risk (Module 6) Score (Follow-up Phase)

SIBAT was specifically developed to measure rapid change in suicidality, based on concerns that existing scales such as BSS are not designed to discriminate differences associated with rapid change. Patient-rated section includes following modules: Module 1 (M-1)(demographic information,suicide history), M-2(current suicidal thinking),M-3 (protective factors), M-4 (suicide behavior),M-5(suicide risk),M-6(suicide-implicit association test).Patient-reported global assessment of suicide risk summarizes patient's judgment of suicide risk (Module 6). Scores: 0(None), 1(Very weak), 2(Weak), 3(Moderately weak), 4(Mild), 5(Moderate), 6 (Moderately strong), 7(Strong), 8(Extremely strong), 9(Extremely strong,constant). Negative change in score indicates improvement. LOCF approach used for missing visit data in ITT LOCF efficacy analyses, last post baseline observation was carried forward as the "End Point" follow up phase.

Time frame: Baseline (Day 1-predose) to Follow-up Phase Endpoint (Day 81)

Change From Baseline to Day 1: 4-Hours Postdose in Beck Scale for Suicidal Ideation (BSS) Total Score (Double-blind Phase)

BSS is 21-item self-reported instrument to detect and measure severity of suicidal ideation. BSS measures broad spectrum of attitudes and behaviors associated with risk of suicide. Items in scale assess respondent's suicidal plans, deterrents to suicide, level of openness to revealing suicidal thoughts. First 19 items of scale measure gradations of severity of suicidal wishes,attitude, plans.Statements reflect increasing gradations of this severity,are scored from 0 to 2. Final two items ask about number of suicide attempts, seriousness of intention to die associated with last attempt,they are not used in calculating BSS total score. Total BSS score represents severity of suicide ideation, calculated by summing ratings of first 19 items;total score ranges from 0 to 38, with higher score representing greater suicide ideation. LOCF approach used for missing visit data in ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 1: 4-hours postdose

Change From Baseline to Day 2 in Beck Scale for Suicidal Ideation (BSS) Total Score (Double-blind Phase)

BSS is 21-item self-reported instrument to detect and measure severity of suicidal ideation. BSS measures broad spectrum of attitudes and behaviors associated with risk of suicide. Items in scale assess respondent's suicidal plans, deterrents to suicide,level of openness to revealing suicidal thoughts. First 19 items of scale measure gradations of severity of suicidal wishes, attitude, plans.Statements reflect increasing gradations of this severity,are scored from 0 to 2. Final two items ask about number of suicide attempts, seriousness of intention to die associated with last attempt,they are not used in calculating BSS total score. Total BSS score represents severity of suicide ideation, calculated by summing ratings of first 19 items;total score ranges from 0 to 38, with higher score representing greater suicide ideation. LOCF approach used for missing visit data in ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 2

Change From Baseline to Double-blind Phase-Endpoint (Day 25) in Beck Scale for Suicidal Ideation Total Score (Double-blind Phase)

BSS is 21-item self-reported instrument to detect and measure severity of suicidal ideation.BSS measures broad spectrum of attitudes and behaviors associated with risk of suicide. Items in scale assess respondent's suicidal plans, deterrents to suicide, level of openness to revealing suicidal thoughts. First 19 items of scale measure gradations of severity of suicidal wishes, attitude, plans.Statements reflect increasing gradations of this severity,are scored from 0 to 2. Final two items ask about number of suicide attempts, seriousness of intention to die associated with last attempt,they are not used in calculating BSS total score. Total BSS score represents severity of suicide ideation, calculated by summing ratings of first 19 items;total score ranges from 0 to 38, with higher score representing greater suicide ideation. LOCF approach used for missing visit data in ITT LOCF efficacy analyses. Last post baseline observation was carried forward as "End Point" for double-blind phase.

Time frame: Baseline (Day 1-predose) to Double-blind Phase-endpoint (Day 25)

Change From Baseline to Follow-up Phase-Endpoint (Day 81) in Beck Scale for Suicidal Ideation Total Score (Follow-up Phase)

BSS is 21-item self-reported instrument to detect and measure severity of suicidal ideation. BSS measures broad spectrum of attitudes and behaviors associated with risk of suicide. Items in scale assess respondent's suicidal plans, deterrents to suicide, level of openness to revealing suicidal thoughts. First 19 items of scale measure gradations of severity of suicidal wishes, attitude, plans.Statements reflect increasing gradations of this severity,are scored from 0 to 2. Final two items ask about number of suicide attempts, seriousness of intention to die associated with last attempt,they are not used in calculating BSS total score. Total BSS score represents severity of suicide ideation, calculated by summing ratings of first 19 items;total score ranges from 0 to 38, with higher score representing greater suicide ideation. LOCF approach used for missing visit data in ITT LOCF efficacy analyses, last post baseline observation was carried forward as the "End Point" follow up phase.

Time frame: Baseline (Day 1-predose) to Follow-up Phase-Endpoint (Day 81)

Change From Baseline to Day 1: 4-Hours Postdose in Beck Hopelessness Scale (BHS) Total Score (Double-blind Phase)

BHS is paper-based self-reported measure to assess one's level of negative expectations or pessimism regarding future. Consists of 20 true-false items that examine the respondent's attitude over past week by either endorsing a pessimistic statement or denying an optimistic statement; 9 are keyed false and 11 are keyed true. Items fall within 3 domains: feelings about future; loss of motivation; future expectations. each response is assigned a score of 0 or 1. Total BHS score is sum of item responses, with range from 0 to 20, with a higher score representing higher level of hopelessness. Total scores that range from 0 to 3 are (normal range), scores 4 to 8 (mild hopelessness, scores 9 to 14 (moderate hopelessness), scores \<14 (severe hopelessness). Negative change in score indicates improvement. The LOCF approach was used for missing visit data in the ITT LOCF efficacy analyses.

Time frame: Baseline (Day 1-predose) to Day 1: 4-hours Postdose

Change From Baseline to Double-blind Phase-Endpoint (Day 25) in Beck Hopelessness Scale Total Score (Double-blind Phase)

BHS is paper-based self-reported measure to assess one's level of negative expectations or pessimism regarding future. Consists of 20 true-false items that examine the respondent's attitude over past week by either endorsing a pessimistic statement or denying an optimistic statement; 9 are keyed false and 11 are keyed true. Items fall within 3 domains: feelings about future; loss of motivation; future expectations. each response is assigned a score of 0 or 1. Total BHS score is sum of item responses, with range from 0 to 20, with a higher score representing higher level of hopelessness. Total scores that range from 0 to 3 are (normal range), scores 4 to 8 (mild hopelessness, scores 9 to 14 (moderate hopelessness), scores \<14 (severe hopelessness). Negative change in score indicates improvement. The LOCF approach was used for missing visit data in the ITT LOCF efficacy analyses. The last post baseline observation was carried forward as the "End Point" for the double-blind phase.

Time frame: Baseline (Day 1-predose) to Double-blind Phase-Endpoint (Day 25)